This application is based on Japanese Patent Application No. 2000-291171, filed Sep. 25, 2000, the contents of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an information processing system and a resume processing method employed in the system, and more particularly to an information processing system capable of resuming its operating environment at the point at which execution was suspended, and a resume processing method employed in the system.
2. Description of the Related Art
Various types of portable computers that can be driven by a battery, e.g. notebook-type personal computers, PDAs, etc., have been developed recently. These computers have a power save mode (sleep mode) for reducing the power consumption. A suspend mode is a least power consuming sleep mode. When a computer system is in suspend mode, almost all devices incorporated therein, except for a memory that stores system data necessary for resuming its operating environment, are powered off.
The system data saved in the memory concerns the status of the CPU and various devices. Further, the memory also stores the status of the operating system and application programs, and user data created by the application programs. When the suspended system is again powered on, the system data saved in the memory is restored, thereby resuming the operating environment at the point at which execution was suspended.
The system data is saved by a suspend routine included in a BIOS (Basic Input Output System). The BIOS is provided for controlling the hardware of the system in accordance with commands from the operating system, and includes device drivers for controlling various hardware devices in the system. The suspend routine in the BIOS is activated when, for example, the power switch of the system is turned off, thereby saving the status of the register of the CPU and those of various peripheral LSIs, before the computer is completely powered off. The supply of power to the memory is continued, using a battery, during the power-off state of the system. This enables the status of the system and the user data, and hence enables the system to be restored to the pre-suspended state.
However, a technique represented by, for example, ACPI (Advanced Configuration and Power Interface) has been developed recently, which imparts a function of power management to the operating system (OS) of the system. In this technique, the suspend/resume process is executed by the cooperation of the OS and the BIOS under the control of the OS. More specifically, the resume process is executed in two stagesxe2x80x94the first resume process is executed by the BIOS and the next resume process is executed by the OS.
In the BIOS resume process, the OS and each device under the control of the OS are restored to respective operation-guaranteed states. Thereafter, the system control is switched from the BIOS to the OS, and resume processing under the control of the OS is started. As a result of this resume process, each device is restored to its original state assumed before its operation was suspended.
However, computer systems are generally comprised of a large number of devices. Therefore, in a resume mechanism in which the OS resume process is executed after the BIOS resume process for all the devices is completed, the OS resume process cannot be started even on a device having been subjected to the BIOS resume process, unless all the devices are subjected to the BIOS resume process. This means that a long pause occurs and hence a lot of time is required for restoring the system.
It is the object of the present invention to provide an information processing system and a resume processing method used therein, which requires a short time to restore the system to its normal operation mode from a power save mode, such as a suspend mode.
To attain the object, there is provided an information processing system capable of resuming an operation, by using system data saved in a memory immediately before the system was suspended, comprising: means, responsive to occurrence of a wakeup event while the system is in a suspended state, for causing a BIOS program to execute a resume sub-process to restore an operation environment of a system core necessary to operate an operating system, the resume sub-process being included in a first resume process executed by the BIOS program; means, responsive to completion of the resume sub-process, for causing the operating system to start execution of a second resume process for restoring an operating environment of each of devices other than the system core; and means for inserting interrupt processes in which the BIOS program executes a remaining resume sub-process of the first resume process, into the second resume process, so as to execute the remaining resume sub-process and the second resume process in a parallel manner, the remaining resume sub-process including a preprocess for enabling the devices to be subjected to the second resume process.
In this system, the first resume process executed by the BIOS program is divided into two sections. When a resume sub-process, included in the first resume process, for restoring the operating environment of a system core necessary for operating the operating system, has been executed, system control is switched from the BIOS program to the operating system. After that, interrupt processes are inserted the second resume process. In the interrupt processes, the BIOS program executes the remaining sub-processes of the first resume process. As a result, the remaining sub-processes of the first resume process and the second resume process by the operating system are executed in a parallel manner. This can shorten the time required for the entire resume process, compared to a sequential process in which the operating system can only execute the second resume process after the BIOS has completed the first resume process on all the related devices.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.